The PRIMARY structure of the protein is quite straight forward but the SECONDARY may need a bit more elaborating on that is, features such as the alpha helix and beta pleated sheet. Description from biochemninja.wordpress.com. I searched for this on bing.com/images
A look at the diversity of structures in the PDB archive. These images, shown to scale, were created by David S. Goodsell (The Scripps Research Institute), who also writes and illustrates the RCSB PDB's Molecule of the Month feature. An expanded version of this figure is available for download from http://www.pdb.org .